Kobayashi-Royden pseudometric vs. Lempert function

Abstract

We give an example showing that the Kobayashi-Royden pseudometric for a non-taut domain is, in general, not the derivative of the Lempert function.Comment: An essential mistake has been corrected in v2. Improved example in v3. v4: minor changes according to the referee remarks (Ann. Mat. Pura Appl.